refactor: no comments left - one-line module docstrings, contracts on public fields only; jobs/job.py; example config and README

src/beaver_gateway/conversations/rotation.py

@@ -1,11 +1,7 @@
-"""Master rotation (§4.5, §8.1, §8.3).
+"""Master rotation: one logical master thread, many physical sessions.
 
-One logical master thread, many physical sessions: when the policy says
-so, a new master is spawned and takes over the window atomically, the old
-one writes its handout as its last turn, closes, its finished branches get
-marked in their windows, its queued normal injects move over, and the new
-one receives "new day". Silence is measured by the user's messages only -
-injects never extend a day.
+When the policy says so, a new master takes over the window; the old one
+hands out, closes, and its branches and queued normal injects move over.
 """
 
 from __future__ import annotations